Textiles impregnated with an aminoplast resin and a vinyl ester carboxylic acid ester soil release agent

ABSTRACT

DISCLOSED HEREIN IS AN IMPROVEMENT IN A PROCESS FOR IMPARTING SOIL RELEASE CHARACTERISTICS TO TEXTILES WHEREIN THE IMPROVEMENT COMPRISES EMPLOYING AS THE SOIL RELEASE AGENT A WATER-SOLUBLE INTERPOLYMER OF A VINYL ESTER WITH A PARTIAL ESTER OF AN ETHYLENICALLY UNSATURATED DICARBOXYLIC ACID OR ANHYDRIDE.

United States Patent US. Cl. 117-139.4 Claims ABSTRACT OF THE DISCLOSURE Disclosed herein is an improvement in a process for imparting soil release characteristics to textiles wherein the improvement comprises employing as the soil release agent a Water-soluble interpolymer of a vinyl ester with a partial ester of an ethylenically unsaturated dicarboxylic acid or anhydride.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to an improvement in a process for imparting soil release properties to textiles.

Description of the prior art In recent years, durable press textiles, i.e., the Wellknown wash and wear fabrics, have attained great importance in the market place. In general, these fabrics are blends of cellulosic materials, such as cotton or rayon, with polyesters. The durable press feature is attained through reaction of some of the hydroxyl groups of the cellulosic component with one or more aminoplastic resins. The use of such compounds for this purpose as N- methylol acrylamide, dihydroxydimethylolethylene urea, methylolated carbamates, methylolated and butylated melamines, to name but a few, is exemplary. The most important feature of fabrics so treated is that they, or garments prepared therefrom, can be washed in home laundry apparatus and dried to yield a clean garment requiring little or no ironing or similar finishing process. Fabrics so treated have, however, suffered from one serious shortcoming which has stunted their economic growth and prevented the widest possible acceptance from consumers. The problem is that textiles, when treated with aminoplastic resins of the type aforementioned, tend to cling tenaciously to greasy, oily soil and cannot be conveniently cleaned in the usual household washing machine. Certain synthetic fibers, particularly polyesters, do not wet well with water and, further, possess a static electrical charge making them diflicult to clean even in the absence of durable press resins. Thus, the problem is compounded. When such fabrics have become stained with greases and oils it was necessary in the past to have the garment dry cleaned by some non-aqueous process resulting in inconvenience and expense to the consumer, essentially defeating the purpose of using a wash and wear textile. Even then, it Was not always possible to remove the soiled spots satisfactorily.

Early efforts to overcome this problem were directed to the use of various soil resistant coatings and agents d signed to inhibit the soiling of the materials. It was found, however, that even with such soil resistant agents, the fabric eventually became soiled. When this occurred the fabric or garment was washed and, although the original stain or spot was more or less removed, it was found that the removed soil was redeposited during the washing process over the entire fabric thereby imparting a yellowish or tattletale-gray cast and generally diminishing the brightness and freshly laundered appearance. This effect was cumulative and over a period of time the garment became aesthetically unacceptable to the wearer and had to be prematurely discarded.

To be differentiated from the foregoing soil resistant agents are the soil release agents which make possible the facile removal of greasy or oily spots and stains during ordinary washing cycles and at the same time prevent redeposition of the soil upon fabric. A number of materials have been suggested for this use, notable among them being salts of interpolymers of styrene and maleic anhydride and emulsion polymers of acrylic acid and its homologues. The styrene maleic anhydride salts suffer from at least one serious drawback in that they must be app ied to the textiles in a two step process; that is to say, they cannot be blended in the same bath with the aminoplastic resin and catalyst therefor and applied to the textile in a single step. The necessity of such additional step adds greatly to the manufacturing cost, which is, of course, reflected in the market price. The acrylic acid emulsions referred to above, when incorporated with the aminoplastic resin and catalyst therefor, have displayed an acceptable combination of durable press characteristics with soil release characteristics. Such emulsions, however, have the disadvantage that they must be shipped from the manufacturer to the textile coater as emulsions thereby making necessary the added expense of shipping relatively large quantities of water which will ultimately be discarded after the coating process. This naturally increases the shipping costs which, again, ultimately are paid for by the consumer.

Acrylic emulsions have also suffered from other deficiencies which have hindered their general acceptance in the industry. As catalysts for the reaction between the aminoplastic resin and the fabric substrate, by means of which the durable press characteristics are imparted, zinc salts are preferred since it is with such salts that the most rapid cures are effected. Acrylic emulsions, however, are incompatible with zinc salts and thus, either a slower acting catalyst must be used or a two bath system, one containing the durable press components and the second containing the soil release components must be used. As pointed out above, such a two-step process is economically unattractive. At least two other problems also arise when acrylic emulsions are applied to the textiles. The process for applying these coatings comprises applying them to the fabric by means of dipping the fabric into a pad bath containing the soil release agent. The fabric is then conducted through nip rolls to remove the superfluitance. Emulsion systems are unstable under the shear induced thereby and tend to coagulate and adhere to the rolls. A deposit thus builds up on the rolls which is redeposited unevenly upon fabric passing through the rolls at a later time. After this step, the fabric is run over a series of heated drying rollers or cans in order to permit most or all of the water from the pad bath to evaporate. Again, it has been found that with the acrylic emulsions of the prior art, the fabric coating tends to adhere to the heated cans and accumulate thereon forming a film or coating of soil release agent on the can itself. This coating must then be removed or it will tend to be pulled off the can at a later time and adhere to fabric then passing over it.

It is known that water-soluble copolymers of maleic anhydride with vinyl acetate can be used as soil release agents which overcome many of the deficiencies noted above. It has been found however, that while these copolymers are effective with some stains, such as for example, yellow mustard, they are inadequate to meet industry standards with regard to stains more diflicult to 3 remove, such as for example, motor oil, particularly dirty, carbon-containing motor oil.

A need, therefore, exists for a soil release agent which may be used in conjunction with a durable press resin, which may be applied to fabric in a single step, which will not adhere to drying cans or nip rolls and which will exhibit improved soil release power with stains such as those caused by dirty motor oil and will, at the same time, have the ability to release other stains at least as well as the soil release agents of the prior art.

SUMMARY OF THE INVENTION The present invention relates to an improved process for imparting durable press and soil release properties to textiles. More particularly, the present invention relates to an improvement in a process for imparting soil release and durable press characteristics to textile materials, said process comprising applying to said textile material an aminoplastic textile resin having N-alkylol functionality, a textile resin catalyst and a water-soluble soil release agent, wherein the improvement comprises employing as the soil release agent an interpolymer of:

(A) a polymerizable vinylidene ester and (B) a partial ester compound interpolymerizable therewith selected from the group consisting of partial esters of ethylenically unsaturated aliphatic dicarboxylic acids and anhydrides containing from 48 carbon atoms and mixtures thereof; said dicarboxylic acid anhydride having up to half of its acidic hydrogen atoms replaced by lower alkyl groups of 18 carbon atoms and mixtures thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The process improvement to which the present invention relates comprises employing as the soil release agent an interpolymer of (A) a polymerizable vinyl ester and (B) a partial ester compound interpolymerizable therewith selected from the group consisting of partial esters of ethylenically unsaturated aliphatic dicarboxylic acids and anhydrides containing 4 to 8 carbon atoms and mixtures thereof, said dicarboxylic acid or anhydride having up to half of its acidic hydrogen atoms replaced by lower alkyl groups of l8 carbon atoms and mixtures thereof.

Any polymerizable vinyl ester may be used in the practice of this invention insofar as it is consonant with the requirement of water solubility of the copolymer to be formed. Among those esters which may be employed are for example, vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pentanoate, vinyl hexanoate, vinyl heptanoate, vinyl octanoate, vinyl isobutyrate, vinyl isopropionate, vinyl secondary-butyrate, vinyl tertiarybutyrate, vinyl 2-ethyl butyrate, vinyl ethylhexanoate, and the like and mixtures thereof.

Suitable as the dicarboxylic acids and anhydrides containing 4-8 carbon atoms from which the partial ester moiety may be derived are, for example, maleic acid, maleic anhydride, fumaric acid, glutaconic acid, alphahydromuconic acid, beta-hydromuconic acid and the like and mixtures thereof. The partial esters are derived from such compounds as these by reaction with alcohols to form alkyl esters having 1-8 carbon atoms in the ester moiety. Any alcohol having 18 carbon atoms or mixtures of such alcohols may be used. Among those suitable are methanol, ethanol, propanol, butanol, pentanOl, hexanol, heptanol, octanol, their isomers and mixtures thereof. Up to half of the carboxyl groups of the dicarboxylic acid or anhydride moiety may be thus reacted in order to form the partial ester. The esterification reaction may be carried out by reacting the alcohol first with the dicarboxylic acid or anhydride monomer and then copolymerizing this esterified monomer with the vinylidene ester monomer or, alternatively, the vinylidene ester and the dicarboxylic acid or anhydride may first be copolymerized and then esterified. The invention herein lies in the discovery that esterification of the acid moiety of the soil release interpolymer, either before or after polymerization, results in a soil release agent having improved properties. It has been found that, other factors being equal, the degree of improvement is proportional to the extent of the esterificationup to and including the 100 mole percent half-ester. Imposed upon this, however, is the further requirement that the copolymer resin to be used as the soil release agent of this invention be watersoluble and compatible with the other components of the system, e.g. the aminoplastic textile resin and catalyst therefor. In view of this, it is not possible to set precise limits on the extent of the esterification, since a longchain ester will adversely affect water-solubility at a lower concentration than will a short-chain ester. In practice, as little as a three mole percent of a Z-ethylhexyl half-ester has shown improved soil release characteristics. It has been found that soil release agents which lie in the range of 10-100 mole percent half-ester give acceptable results based on industry standards. A more preferred range is 40l00 mole percent.

It is most surprising that esterification should have the effect of enhancing soil release properties. In the past, soil release ability has been equated with the presence of an acidic functionality, e.g. a COOH group. It has now been discovered that esterification, which decreases the concentration of the acidic function, acts in a Way opposite to that which would have been predicted and improves soil release.

It has been discovered that the molecular weight of the soil release interpolymer affects the soil release propertiesthe higher the molecular weight, the greater the improvement. An increase in molecular weight also improves the durability under continued use of the soil release agent after it has been applied to the textile. Thus, it is advantageous to employ as high a molecular weight interpolymer as is consonant with the necessity of maintaining a workable viscosity in aqueous solution.

Any aminoplastic resin having N-alkylol functionality may be used in conjunction with the soil release agents of this invention provided that such aminoplastic resin is water-soluble or dispersible. Among those resins which have been found to be particularly useful in the practice of this invention are the condensates of an aldehyde, especially formaldehyde, with urea, N,N'-ethylene urea, N,N'-trimethylene urea, an aminotriazine, such as melamine, a carbamate or a S-substituted-tetrahydro-s-triazone-2. In addition, N-methylol acrylamide, while not strictly an aminoplastic resin, may be used as the N-methylol functionality-contributing moiety if provision is made for its subsequent resinification. The preferred aminoplastic resin for use in the practice of this invention is dihydroxydimethylol ethylene urea; (DHDMEU) because it furnishes the optimum in durable press qualities to the fabric. As catalysts for the reaction between the aminoplastic resin and the textile substrate, any of the catalysts generally used for such purpose and known in the art may be employed. Among those which are particularly useful are, for example, magnesium chloride, zinc nitrate, zinc fiuoroborate and salts of amines such as monoethanolamine hydrochloride and 2-amino-2- methyl propanol nitrate and the like and mixtures of the foregoing.

The soil release agents of this invention may be used as above described, i.e., as partial esters having free acid groups remaining on the dicarboxylic acids. However, it has been found that neutralization of at least a portion of the remaining carboxylic acid groups results in a composition having even further improved soil release capabilities. Thus, the carboxylic function may be neutralized with basic compounds derived from alkali metals, such as lithium, sodium, potassium, rubidium and caesium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium; zinc; amines and ammonia. Mixtures of the foregoing may also be employed. Among the amines which may be used are, for example, primary, secondary, tertiary, alkyl and alkanol amines such as, for example, methylamine, diethylamine, tripropylamine, trimethanol amine, dipropanolamine, ethanolamine, N- ethyl-N-methyl-propylamine, N,N-dimethy1 butylamine, N-ethyl dipropylamine, etc. Quaternary ammonium compounds containing a free OH group may also be used.

The improved soil-release agents of this invention may be applied to a wide variety of textile fibers, both natural and synthetic, and to the fabrics manufactured therefrom. Exemplary of these fibers are polyesters, cotton, polyacrylonitrile polymers and copolymers, linen, wool, silk, regenerated cellulosics, polyolefins, nylons, etc. and blends thereof. A further understanding of the compositions, processes and textile products of this invention will be obtained from the following specific examples which are intended to illustrate the invention but not to limit the scope thereof, parts and percentages being by weight unless otherwise specified.

EXAMPLE I Part A Dissolve parts by weight of a partial methyl ester of a 1/1 vinyl acetate/maleic anhydride copolymer in 90 parts by weight of water. In this partial ester, mole percent of the total carboxyl groups of the maleic anhydride moiety have been esterified. This is referred to as the 50% half-ester. To the solution thus prepared is added sufficient calcium hydroxide to neutralize one-half of the unesterified carboxyl groups.

Part B A pad bath solution is prepared by adding 24 parts of water to parts of dihydroxy dimethylol ethylene urea solution containing 45% solids in water. To this solution is added 6 grams of magnesium chloride hexahydrate. The solution is agitated and parts of the solution of Part A is added thereto.

Part C The pad bath solution of Part B is applied to a 65/35 polyester/cotton batiste fabric by dipping into a trough containing the solution and then squeezing between two rolls to remove excess solution. Wet pickup is found to be about 90%. The coated sample is then attached to a conventional pin frame, dried at 220 F. for 3 minutes andthen cured at 320 F. for 2 minutes.

Part D A sample of the treated textile of Part C is tested for durable press using AATCC 88A1964T, the standard test method for evaluating the appearance of fabrics in wash and wear items after home style laundering. The same is found to have an improved appearance as compared to an untreated fabric, the value observed with treated fabric by test method 111-C-1 being 4.1 and with untreated fabric is 1.8.

Part E Wrinkle recovery of the treated fabric of Part C is tested by AATCC test method 66-1959T. The crease recovery angle on the warp plus fill is found to be 270.

As a control, a similar fabric is padded with water, run through the same drying and cure cycle and then tested for wrinkle recovery in the same manner. In this case, the crease recovery angle is 248.

Part F The treated fabric of Part C is washed in conventional home laundry apparatus with water at 140 F. using the commercial detergent TIDE, marketed by Proctor and Gamble. It is then tumbled in a conventional dryer at the regular setting for minutes. The sample is then conditioned in a constant temperature-humidity room at 73 F. and RH. The fabric is then stained by applying thereto a single spot of a commercially available non-detergent, SAE-20 motor oil containing 0.63 added carbon black. The oil is left on the fabric for 30 seconds and then the excess is removed by wiping with a soft cloth. The spotted fabric is then aged for 30 minutes at room temperature and then washed and dried as described above. The residual stain is then determined by visual comparison against a set of standards, known in the textile industry as the Deering-Milliken Research Corporation Photographic Standards using AATCC overhead lighting equipment for viewing the test specimens. Evaluation of the residual stain is carried out both by placing the spotted fabric upon a black and upon a white background. The visual results are compared and re corded against the Deering-Milliken photo standards of 1 through 5, wherein 1 represents high stain and 5 represents complete removal. By this test, the fabric treated as above has a value of 2.8 when observed against the White background and 3.6 when observed against the black background. Under similar conditions, fabrics treated with the soil release agents of this invention are highly eifective against other kinds of stains, e.g., with a commercially available vegetable cooking oil, the soil release value is 4.0; with a commercially available mineral oil, 4.1 and with a salad-type mustard which, as purchased, contains a yellow vegetable dye, 3.6.

Part G As a control, Parts A, B, C and F are repeated, except that no soil release agent is applied to the fabric. Instead, the 10 parts of the methyl half-ester is replaced by 10 parts of water. This time, the soil release value for the carbon containing motor oil viewed against a white background is 1.0, thus demonstrating the improvement in soil release exhibited by fabrics treated with the agent of this invention as compared to untreated, durable press fabrics.

EXAMPLE II Part A.-Contro1 As a control, a copolymer of vinyl acetate and maleic anhydride having 5 0% of its carboxyl groups neutralized with magnesium hydroxide is substituted for the textile treating agent of Example I. The specific viscosity of this resin is 1.70 as a 1% solution in cyclohexanone. By the test of Example I, Part F, the stain release value for carbon-containing motor oil, measured against a white background is only 2.1.

Part B In order to cancel out the variable of molecular weight and thereby obtain a clear showing of the beneficial effect of esterification, the vinyl acetate/maleic anhydride copolymer of Part A is 41% half-esterified with methanol. Fifty percent of the remaining carboxyl groups are neutralized with magnesium hydroxide. When tested as in Part A, the soil release value is found to have increased to 2.8.

Part C The vinyl acetate/maleic anhydride copolymer of Part A is half-esterified 'with methanol and 50% of the remaining unesterified carboxyl groups are neutralized with magnesium hydroxide. This time the soil release value is found to have increased to 3.5

The example demonstrates that, other effects being equal, soil release is substantially improved by esterification and this improvement is proportional to the extent of the esterification.

Examples III-XII shown in Table I, infra, demonstrate the effectiveness of the soil release agents of this invention when percentage and type of half-ester is varied. Specific viscosity values of 1% solutions of the copolymer esters in cyclohexanone are included as indications of molecular weight. Soil release values are for non-detergent, SAE-20 motor oil containing 0.63% added car- 7 bon black. Results are as viewed against a white background.

It is obvious that many additions and modifications may be made to this invention without departing from the spirit and scope thereof.

What is claimed is:

1. A textile material impregnated with an aminoplast textile resin having N-alkylol functionality and a soil re lease agent comprising an interpolymer of (A) a polymerizable vinyl ester; and

(B) a partial ester compound interpolymerizable therewith selected from the group consisting of partial esters of ethylenically unsaturated aliphatic dicarboxylic acids and anhydrides containing from 4 to 8 carbon atoms and mixtures thereof; said dicarboxylic acid or anhydride having up to half of its acidic hydrogen atoms replaced by lower alkyl groups of 1 to 8 carbon atoms and mixtures thereof and from to 100% of the remaining acidic hydrogen atoms neutralized with at least one compound selected from the group consisting of basic compounds derived from alkali metals, alkaline-earth metals, zinc, aliphatic amines, ammonia and quaternary ammonium compounds containing a free hydroxyl group.

2. The textile material of claim 1 wherein the polymerizable vinyl ester is vinyl acetate.

3. The textile material of claim 1 wherein the partial ester is the partial methyl ester of a vinyl acetate/maleic anhydride copolymer.

4. A textile material impregnated with an aminoplastic textile resin having N-alkylol functionality and a soil release agent comprising an interpolymer of (A) vinyl acetate; and

(B) a to 100 mole percent half ester of maleic anhydride wherein the ester groups are lower alkyl groups of from 1 t0 8 carbon atoms and mixtures thereof; and wherein from 0 to of the remaining acidic hydrogen atoms are neutralized with at least one compound selected from the group consisting of basic compounds derived from alkali metals, alkaline-earth metals, zinc, aliphatic amines, ammonia and quaternary ammonium compounds containing a free hydroxyl group.

5. The textile material of claim 4 wherein the ester of maleic anhydride is selected from the group consisting of methyl and ethyl esters of maleic anhydride.

6. The textile material of claim 4 wherein the ester is a 40' to 100 mole percent half methyl ester of maleic anhydride.

7. The textile material of claim 4 wherein the aminoplastic textile resin having N-alkylol functionality is dihydroxy dimethylol ethylene urea.

8. The textile material of claim 4 wherein at least a portion of the remaining carboxylic groups are neutralized with a metal selected from the group consisting of alkali and alkaline earth metals.

9. The textile material of claim 4 wherein the interpolymer is a U1 interpolymer of vinyl acetate and the methyl ester of maleic anhydride wherein the ester content is in the range of from 40 to 100 mole percent half ester.

10. A textile material impregnated with an aminoplastic textile resin having N-alkylol functionality and a soil release agent comprising a 1/1 interpolymer of (A) vinyl acetate; and

(B) a 40 to 100 mole percent half methyl ester of maleic anhydride wherein from 0 to 100% of the remaining acidic hydrogen atoms are neutralized with at least one compound selected from the group consisting of basic compounds derived from alkali metals, alkaline-earth metals, zinc, aliphatic amines, ammonia and quaternary ammonium compounds containing a free hydroxyl group.

References Cited UNITED STATES PATENTS WILLIAM D. MARTIN, Primary Examiner T. G. DAVIS, Assistant Examiner U.S. Cl. X.R.

l17-l39.5, 161; 8ll5.6 

